Calculator Categories

8 categories covering 163 free tools: payroll, finance, health, construction, education, math, food, and more. No sign-up required.

Not sure where to start? Each category below links to a full list of calculators with descriptions. Pick a category that matches your task: estimating take-home pay, planning a home renovation, tracking a health metric, or running a financial projection.

Payroll & Tax
50+ calculators
Illinois Paycheck Calculator
Federal Income Tax Rate Calculator
Ohio Paycheck Calculator
Self-Employment Tax Calculator
Prorated Rent Calculator
Time and a Half Calculator
+ 48 more calculators
Browse Payroll & Tax Calculators →
Construction & Materials
21+ calculators
Square Footage Calculator
Asphalt Calculator
Roof Pitch Calculator
Bitumen Calculator
Board Feet Calculator
Conduit Fill Calculator
+ 14 more calculators
Browse Construction & Materials Calculators →
Health & Fitness
24+ calculators
Period Calculator
Chronological Age Calculator
Starbucks Calorie Calculator
A1C Calculator
ABV Calculator
Corrected Calcium Calculator
+ 17 more calculators
Browse Health & Fitness Calculators →
Finance & Investment
20+ calculators
Reverse Mortgage Calculator
Coast FIRE Calculator
FERS Retirement Calculator
Cap Rate Calculator
Commercial Mortgage Calculator
Silver and Scrap Metal Calculator
+ 14 more calculators
Browse Finance & Investment Calculators →
Education & GPA
16+ calculators
High School GPA Calculator
APUSH Score Calculator
AP Lang Score Calculator
ACT Score Calculator
Semester Grade Calculator
SAT Score Calculator
+ 10 more calculators
Browse Education & GPA Calculators →
Math & Science
10+ calculators
Antiderivative Calculator
Matrix Determinant Calculator
Acceleration Calculator
Interpolation Calculator
Mean Median Mode Calculator
Correlation Coefficient Calculator
+ 4 more calculators
Browse Math & Science Calculators →
Food & Cooking
8+ calculators
Restaurant Calorie Calculators
Pizza Calculator
Turkey Cooking Time Calculator
Pizza Dough Calculator
Food Cost Calculator
Recipe Conversion Calculator
+ 2 more calculators
Browse Food & Cooking Calculators →
Specialty & Other
15+ calculators
RVU Calculator
ERA Calculator
MAP Calculator
Pool Salt Calculator
Crosswind Calculator
Binomial Distribution Calculator
+ 6 more calculators
Browse Specialty & Other Calculators →

Frequently Asked Questions

Questions about browsing and using CalculatorFlux calculators.

CalculatorFlux organizes its 163 calculators into 8 categories: Payroll and Tax (50+ tools covering all US states), Finance and Investment, Health and Fitness, Construction and Materials, Education and GPA, Math and Science, Food and Cooking, and Specialty tools.

Use the Payroll and Tax category. It includes state-specific paycheck calculators for all 50 US states and Washington DC, plus tools for self-employment tax, overtime pay, prorated rent, and reverse sales tax. All are updated for 2025-26.

All health tools are in the Health and Fitness category. This includes A1C, VO2 Max, BAC, peptide dosage, baby percentile, and calorie calculators for popular restaurant chains. Every health calculator links to its source formula.

Yes. The Finance and Investment category includes Coast FIRE, Barista FIRE, FERS Retirement, 401k with Match, Roth IRA Contribution, Roth vs Traditional 401k, and Dividend DRIP calculators alongside mortgage, cap rate, and debt payoff tools.

Yes. Visit the Contact page and describe the calculator you need. We review every request and prioritize tools that fill real gaps for a broad audience.